Validated simulations of indirectly-driven ICF implosions in the I-Raum

A new shaped hohlraum design has recently been experimentally tested on NIF, and the results are presented in a companion talk by Ross et al. This new hohlraum, called the I-Raum [1], was specifically designed to improve late-time inner-beam propagation to the hohlraum equator by adding a localized pocket of increased wall radius at the location where the outer beam cones hit the hohlraum wall. This simple modification displaces the growing bubble of Au wall material to larger radius at all times throughout the implosion, thereby improving inner beam propagation and the resulting implosion symmetry. Integrated hohlraum simulations using HYDRA are benchmarked to the recent experimental results, providing a validated methodology for more accurate prediction of future implosions using this new hohlraum.

[1] H. F. Robey et al., “The I-Raum: A new shaped hohlraum for improved inner beam propagation in indirectly-driven ICF implosions on the National Ignition Facility”, Phys Plasmas 25, 012711 (2018).